compression test

[drknute3]

I apologize for not being able to find it on here but can someone give me the step by step run down on doing a compression test on a 2000 Volvo penta 5.0?

Also wondering if someone could tell me how they get such different HP ratings in the 5.0 series. Why the 5.0GL has only 220hp, but the GI has 250 and the GXI has 270. All are 5.0 engines.

Thanks
Bill

 

[drknute3]

Re: compression test

Found a link descibing the process. Do I need to remove all the spark plugs at once or can I remove them one at a time and check that cylinder?

 

[JustJason]

Re: compression test

technically your supposed to removes them all at once to increase your cranking rpm......
realistically.... 1 at a time is fine.... just make sure you have a good battery.

 

[Bondo]

Re: compression test

Also wondering if someone could tell me how they get such different HP ratings in the 5.0 series.

Ayuh,....

My Guess is,....
2bbl. Carb,... 4bbl. Carb,... EFI,....

 

[danond]

Re: compression test

Pull all the plugs, you will get a lower reading if your engine turns over slowly with all of them in. Some turn slowly in general for various reasons and you want to get the best reading you can get.

 

[Don S]

Re: compression test

Here is a link to the Mercruiser service bulletin on how to do a compression test. It's almost word for word of Volvo's information. It all comes from Chevy, wonder why it's the same
http://www.boatfix.com/merc/Bullet/97/97_25.pdf

 

[danond]

Re: compression test

You're not suggesting....

Naw.